A slitter line that continuously cuts a long and wide sheet-like metal strip along the longitudinal direction into a plurality of strips while winding multiple strips simultaneously, has been used. The metal strip is cut into predetermined widths according to the use of metal coils, and ten or more strips may be made from one plate.
In a slitter line, after a metal plate is slit into multiple strips, the multiple strips are wound by a winding machine. At this time, by a tensioner provided before the winding machine, the strips are tensioned and then tightly and firmly wound into wound coils.
A sheet-like metal strip to be supplied to the slitter line is generally manufactured by rolling. Therefore, both end portions of the metal strip become thinner than the center portion, so that the thickness differs in the same sheet.
At the time of slitting, pointed burrs are generated only on the end faces of each strip, and this may cause thickness differences.
When strips are wound by the winding machine after being slit, thickness differences of the sheet or thickness differences caused by burrs become diameter differences of the wound coils. That is, a wound coil diameter of a strip with a thickness difference becomes larger than a wound coil diameter of a strip with a small thickness, and a circumferential length difference occurs between these, so that the strip to be wound into a wound coil with a larger coil diameter is wound faster.
Due to this winding speed difference, a length difference occurs between strips at a position on the downstream side of the slitter of the slitter line, and the strips form loops with different sizes. If the surface of the strip comes into contact with the floor or the like, it is damaged and its commercial value is deteriorated, so that a loop pit with a depth of several meters is provided at a position of looping on the floor surface so as to temporarily store the loops.
However, in the structure in which a loop pit is provided, the loop absorbing amount depends on the depth of the loop pit, and provision of an extremely deep loop pit is not preferable in terms of the facility cost. In addition, it is necessary that the line be stopped before the largest loop of multiple strips comes into contact with the loop pit bottom surface, and the metal coils wound until that point be separated midway and made as products, and this causes lowering of production efficiency.
In recent years, automatization has increased in the industries using strip coils, and long-length coil products have been demanded to enable long-time operation, so that a pit with a depth of 10 meters or more is inevitably dug in actuality. In particular, in electric and electronic industries, coil materials have become thinner and longer, so that the loop amounts of these tend to increase.
Under these circumstances, structures that tried to realize efficient loop absorption exist, and apparatuses described in, for example, Patent Document 1 and Patent Document 2 were proposed.
Here, in Patent Document 1, the absorption apparatus 100 shown in FIG. 22(a) is described. The absorption apparatus 100 is structured to supply a loop 101a, a loop 101b, a loop 101c, and a loop 101d of strips from the loop pit 102 side to the guide roller 104 provided on the holding arm 103. The strips flow from the guide roller 104 to the rolls 105 and the subsequent winding machine 112 side.
The absorption apparatus 100 is structured so that the guide roller 104 is extended to the slitter 106 side via a cylinder device. In Patent Document 1, the absorption apparatus 107 shown in FIG. 22(b) is also described.
The absorption apparatus 107 is structured so that a carriage 109 to which the guide roller 108 is attached moves on a rail 110 extended in the horizontal direction. Strips flow to the rolls 111 and the subsequent winding machine side via the guide roller 108.
In Patent Document 2, a structure in which an absorption tower having a roll movable up and down is installed by the side of the loop pit, and when a loop sags, the loop is lifted up by the roll of the absorption tower.
As another structure, as shown in FIG. 23, there is also a structure in which a pinch-roll type conveyance roll 114 that pinches strips by two rolls 113 disposed on the upper and lower sides and pushes the strips out to the winding machine side is installed in the looping region so that two-divided loops 116 are formed in the loop pit 115.